DESCRIPTION: The aim of this application is to characterize the role of dissatisfaction (dsf) and doublesex (dsx) in the expression of sexual behaviors by controlling differentiation of sex-specific neurons in Drosophila. Mutations in dsf affect female sexual behavior and altered sexual preference in males. In contrast, dsx appears to regulate the development of somatic tissues in the body. The proposed studies will use a combined molecular, genetic and anatomical approach to determine the expression of dsf or dsx in the nervous system, and to correlate the behavioral phenotype of the animal. Double or triple mutants of fru (fruitless), dsf and dsx, will also be constructed to investigating the genetic interaction. The proposed research will be testing the following hypothesis that three parallel pathways control the sexual development and behavior: the dsx gene controls the sexual development of somatic tissues in the body with little or no indirect role in sexual behavior; the dsf gene regulates female sexual behavior with auxiliary roles in some male sexual behavior; the fru gene controls only male sexual behavior.